sse 推送3版

README.md

@@ -19,4 +19,6 @@
 
 [java实现web实时消息推送的七种方案--个人学习记录](https://blog.csdn.net/weixin_44705301/article/details/128670957)
 
+[springboot SseEmitter 消息推送](https://blog.csdn.net/qq_39992641/article/details/105229674)
+
 

src/main/java/com/xtong/zhbs/controller/TestController.java

@@ -0,0 +1,58 @@
+package com.xtong.zhbs.controller;
+
+
+import com.xtong.zhbs.sse.SseEmitterServer;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+
+@CrossOrigin
+@RestController
+@RequestMapping("/sse")
+public class TestController {
+    /**
+     * 用于创建连接
+     */
+    @GetMapping("/connect/{userId}")
+    public SseEmitter connect(@PathVariable String userId) {
+        return SseEmitterServer.connect(userId);
+    }
+
+    /**
+     * 推送给所有人
+     *
+     * @param message
+     * @return
+     */
+    @GetMapping("/push/{message}")
+    public ResponseEntity<String> push(@PathVariable(name = "message") String message) {
+        SseEmitterServer.batchSendMessage(message);
+        return ResponseEntity.ok("WebSocket 推送消息给所有人");
+    }
+
+    /**
+     * 发送给单个人
+     *
+     * @param message
+     * @param userid
+     * @return
+     */
+    @GetMapping("/push_one/{messsage}/{userid}")
+    public ResponseEntity<String> pushOne(@PathVariable(name = "message") String message, @PathVariable(name = "userid") String userid) {
+        SseEmitterServer.sendMessage(userid, message);
+        return ResponseEntity.ok("WebSocket 推送消息给" + userid);
+    }
+
+    /**
+     * 关闭连接
+     */
+    @GetMapping("/close/{userid}")
+    public ResponseEntity<String> close(@PathVariable("userid") String userid) {
+        SseEmitterServer.removeUser(userid);
+        return ResponseEntity.ok("连接关闭");
+    }
+
+}
+
+

src/main/java/com/xtong/zhbs/sse/SseEmitterServer.java

@@ -0,0 +1,135 @@
+package com.xtong.zhbs.sse;
+
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.MediaType;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+
+/**
+ * sse 服务器端推送消息
+ */
+public class SseEmitterServer {
+
+    private static final Logger logger = LoggerFactory.getLogger(SseEmitterServer.class);
+
+    /**
+     * 当前连接数
+     */
+    private static AtomicInteger count = new AtomicInteger(0);
+
+    /**
+     * 使用map对象，便于根据userId来获取对应的SseEmitter，或者放redis里面
+     */
+    private static Map<String, SseEmitter> sseEmitterMap = new ConcurrentHashMap<>();
+
+    /**
+     * 创建用户连接并返回 SseEmitter
+     *
+     * @param userId 用户ID
+     * @return SseEmitter
+     */
+    public static SseEmitter connect(String userId) {
+        // 设置超时时间，0表示不过期。默认30秒，超过时间未完成会抛出异常：AsyncRequestTimeoutException
+        SseEmitter sseEmitter = new SseEmitter(0L);
+        // 注册回调
+        sseEmitter.onCompletion(completionCallBack(userId));
+        sseEmitter.onError(errorCallBack(userId));
+        sseEmitter.onTimeout(timeoutCallBack(userId));
+        sseEmitterMap.put(userId, sseEmitter);
+        // 数量+1
+        count.getAndIncrement();
+        logger.info("创建新的sse连接，当前用户：{}", userId);
+        return sseEmitter;
+    }
+
+    /**
+     * 给指定用户发送信息
+     */
+    public static void sendMessage(String userId, String message) {
+        if (sseEmitterMap.containsKey(userId)) {
+            try {
+                // sseEmitterMap.get(userId).send(message, MediaType.APPLICATION_JSON);
+                sseEmitterMap.get(userId).send(message);
+            } catch (IOException e) {
+                logger.error("用户[{}]推送异常:{}", userId, e.getMessage());
+                removeUser(userId);
+            }
+        }
+    }
+
+    /**
+     * 群发消息
+     */
+    public static void batchSendMessage(String wsInfo, List<String> ids) {
+        ids.forEach(userId -> sendMessage(wsInfo, userId));
+    }
+
+    /**
+     * 群发所有人
+     */
+    public static void batchSendMessage(String wsInfo) {
+        sseEmitterMap.forEach((k, v) -> {
+            try {
+                v.send(wsInfo, MediaType.APPLICATION_JSON);
+            } catch (IOException e) {
+                logger.error("用户[{}]推送异常:{}", k, e.getMessage());
+                removeUser(k);
+            }
+        });
+    }
+
+    /**
+     * 移除用户连接
+     */
+    public static void removeUser(String userId) {
+        sseEmitterMap.remove(userId);
+        // 数量-1
+        count.getAndDecrement();
+        logger.info("移除用户：{}", userId);
+    }
+
+    /**
+     * 获取当前连接信息
+     */
+    public static List<String> getIds() {
+        return new ArrayList<>(sseEmitterMap.keySet());
+    }
+
+    /**
+     * 获取当前连接数量
+     */
+    public static int getUserCount() {
+        return count.intValue();
+    }
+
+    private static Runnable completionCallBack(String userId) {
+        return () -> {
+            logger.info("结束连接：{}", userId);
+            removeUser(userId);
+        };
+    }
+
+    private static Runnable timeoutCallBack(String userId) {
+        return () -> {
+            logger.info("连接超时：{}", userId);
+            removeUser(userId);
+        };
+    }
+
+    private static Consumer<Throwable> errorCallBack(String userId) {
+        return throwable -> {
+            logger.info("连接异常：{}", userId);
+            removeUser(userId);
+        };
+    }
+
+}

src/main/resources/static/sse.html

@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <title>SseEmitter</title>
+</head>
+
+<body>
+<button onclick="closeSse()">关闭连接</button>
+<div id="message"></div>
+</body>
+<script>
+    let source = null;
+
+    // 用时间戳模拟登录用户
+    const userId = new Date().getTime();
+
+    if (window.EventSource) {
+
+        // 建立连接
+        source = new EventSource('http://localhost:8080/sse/connect/' + userId);
+
+        /**
+         * 连接一旦建立，就会触发open事件
+         * 另一种写法：source.onopen = function (event) {}
+         */
+        source.addEventListener('open', function(e) {
+            setMessageInnerHTML("建立连接。。。");
+        }, false);
+
+        /**
+         * 客户端收到服务器发来的数据
+         * 另一种写法：source.onmessage = function (event) {}
+         */
+        source.addEventListener('message', function(e) {
+            setMessageInnerHTML(e.data);
+        });
+
+
+        /**
+         * 如果发生通信错误（比如连接中断），就会触发error事件
+         * 或者：
+         * 另一种写法：source.onerror = function (event) {}
+         */
+        source.addEventListener('error', function(e) {
+            if (e.readyState === EventSource.CLOSED) {
+                setMessageInnerHTML("连接关闭");
+            } else {
+                console.log(e);
+            }
+        }, false);
+
+    } else {
+        setMessageInnerHTML("你的浏览器不支持SSE");
+    }
+
+    // 监听窗口关闭事件，主动去关闭sse连接，如果服务端设置永不过期，浏览器关闭后手动清理服务端数据
+    window.onbeforeunload = function() {
+        closeSse();
+    };
+
+    // 关闭Sse连接
+    function closeSse() {
+        source.close();
+        const httpRequest = new XMLHttpRequest();
+        httpRequest.open('GET', 'http://localhost:8080/sse/close/' + userId, true);
+        httpRequest.send();
+        console.log("close");
+    }
+
+    // 将消息显示在网页上
+    function setMessageInnerHTML(innerHTML) {
+        document.getElementById('message').innerHTML += innerHTML + '<br/>';
+    }
+</script>
+
+</html>